HSBC Bank Australia contributed US$446 million of pre-tax profit to HSBC Holdings' earnings in 2013 - an increase of 62 per cent over the 2012 contribution.According to group accounts published yesterday, most of the increase came from the commercial banking division, whose pre-tax profit rose from US$38 million in 2012 to US$131 million last year.In 2012 the Australian commercial banking division took a charge against a large impairment of a corporate exposure.The other Australian divisions performed in line with the previous year. The retail banking and wealth management division made a pre-tax profit of US$100 million, compared with $97 million in 2012.The global banking and markets division made a pre-tax profit of US$189 million, compared with US$184 million in 2012.The value of customer accounts in Australia fell US$20.4 billion in 2012 to US$19.8 billion last year.The residential mortgage book increased by 8.5 per cent, while the personal commercial loan books fell slightly.